Thermostatic flue regulator



March 31, 1931. A. c. McwlLLrAMs THERMOSTATIC FLUE REGULATOR Filed Feb. 16, 1929 25 eter.

Patented Mar. 31,v 1931 PATENT OFFICE ARTHUR C.l MC'WILLIAMS, OF CHICAGO, ILLINOIS THERMOSTATIC FL'UE REGULATOR Application filed February 16, 1929. Serial No. 340,567.

My invention relates to dampers for a Hue pipe or the like; and in its general objects aims to provide a damper which can be manually adjusted in position to aii'ord a. desired effective minimum passage through the pipe, and which will automatically increase this minimum passage when the pipe 'cools and annul the increase when the temperature rises.

In operating both coal-burning and oilburning heaters, the eHiciency of such heaters depends to a considerable extent on the eHective sizeof the passage for the combustion gases. The maintaining of a high efficiency involves a much more frequent adjustment than can be expected manually from any attendant, and also requires adjustments more accurately proportioned to the temperature of the gases in the Hue than can be made by an ordinary attendant.

Moreover, with any given heater, the maximum eHective passage through the Hue may also need to be adjusted according to the nature of the fuel and according to the barom- If these adjustments are also left to the average attendant, an error in attending to them may lead to so-called puff-backs with oil burners, and to an extinguishing of the fire in a coal-burning heater,'in addition to increasing the ffuel consumption.

My present invention aims to overcomeall of these objections by providing `a main damper which can be manually adjusted and latched in any one of a number of definitely 35 determined .and positively indicated posif tions, in each of which positions the main damper will afford an effective Hue passage of a definitely known -cross-.section ranging from an approximately full Hue opening to a o partial opening of deHnite proportion to this full Hue opening; and also aims to provide a thermostatically operated secondary damper (or breather vane) which will automati-1 cally increase the afforded Hue opening (when the main damper is notv in its said full open position) in response to temperature changes within the Hue.

Moreover, my invention aims to provlde simple, inexpensive, easily installed and not 5. readily clogged plural damper means for th1s purpose. Still further and also more detailed objects will appear from the following specification and from the accompanying drawings, in which v v Fig. l is a central longitudinal section through a portion of a Hue pipe in which an embodiment of my invention is mounted, taken transversely of the pivot axis of the main damper and showing my plural damper means as positioned-for affording the minimum effective Hue passage for which they'are designed.

Fig. 2 is a reduced section taken transversely of the Hue pipe along the line 2-2 -of Fig. l, when the temperature of the Hue gases is such that the -thermostatic means have partly opened the supplemental gas passages formed in the main damper.

Fig. 3 is a fragmentary plan view, taken from the exterior ofthe Hue pipe alor'g the line 3-3 of Fig. l.

Fig. 4 is a. fragmentary section, similar to the central portion of Fig. 1, but showing another form of thermostatic coil.

In the illustrated embodiment, the Hue pipe 1 is provided with diametrically opposite perforations into which alined bushin s 2 and 3 extend radially of the pipe. S aft portions 4 and 5 extend respectively through the bushings 2 and 3, and each of these shaft portions is secured (as by rivets 6) to the main damper 7 This main damper (which maybe a Hat disk of sheet iron) is provided with a central and square perforation for receiving a correspondingly squarejsectioned end portion 8A of a pivoting shaft which extends at right angles to the face of the main damper 7 and which shaft end portion is riveted to that damper.

Pivoted on the shaft 8 is a secondary damper or breather vane 9 which desirably is spaced from the main damper 7 by a washer 10, to reduce friction. The secondary damper is fastened, as by a .bracket 11, to the outer end of a spirally coiled thermostatic strip 12 made of a metal having a high coefficient of expansion, while the inner end of this coiled strip is secured, as by a rivet 13, to the pivoting shaft 8. This thermally responsive strip is desirably housed by a casing consisting of the radially inner portion of the secondary damper and of a cup-shaped housing 14 which is secured at its mouth to the auxiliary damper. The cup bottom of this housing 14 desirably has a perforation through which a diametrically reduced free end portion 8B of the pivoting shaft extends, so that the auxiliary `damper and housing combination has two spaced bearings in which the pivoting shaft is j ournaled. Then I provide suitable means to prevent this secondary damper and housing combination from sliding along the shaft away from the main damper 7, such as a washer 15 engaging the outer face of the cup bottom anda pin 16 extending through the pivoting shaft outsideof (and adjacent to) this washer.

The two dampers are provided with perforations arranged so that the perforations in the secondary damper will be moved into and out of alinement with the perforations in the main damper when the secondary damper is rotated about the pivoting shaft 8 which is fast upon the main damper. rlhese damper perforations are desirably sectorshaped, as shown in Fig. 2 for the perfora tions 17 in the main damper and the perforations 18 in the auxiliary damper; and the length of the coiled strip 12 is so selected that the coiling and uncoiling of this strip with the excepted temperature changes in the flue pipe will move the secondary damper to and from positionsin which the perforations in the latter damper are either completely in alinement or completely out of alinement with those in the main damper.

Interlocked with one of the main damper shaft 'parts 4 is a resilient latching arm 17 by means ofv which this two-part shaft can.

be rotated. This interlocking is here yshown as made by outwardly turning the end of the latching arm 17 through which thel .said shaft part 4 extends, so that this turned up end 17A bears against a fiat face of a collar 19 which is fastened to the shaft by a pin 20. This collar 19 is suliciently spaced from the outer end of the adjacent journaling bushing 2, so that both the latching arm 17 and a latch plate 22 extend between the collar and the said bushing. The latch plate also is perforated so that the said shaft part 4 extends through it, and is fastened to the flue pipe by a rivet 21. l

This latch plate 22 desirably is substantially quadrant-shaped andhas at its arcuate edge an outwardly directed ange 23 provided with spaced recesses 24 into any one of which the resilient latching arm 17 can snap, after which the walls of entered recess will revent the latching arm from rotating, thereby holding the main damper against rotation in the fine. The latch plate also is desirably marked to indicate the closed and open kpositions between which the main damper is movable, thereby indicating to the user the minimum effective flue passage for which my composite damper has been set.

When the main damper is thus adjusted, the minimum i'iue passage is definitely fixed, and if the iue is at the minimum temperature for which the thermostatic coil 12 is constructed, this coil holds the secondary damper (or breather vane) in a position in which the apertures 17 in that damper aline with the apertures v18 in the main damper, thus affording the maximum additional passage area past the main damper. However, when the temperature in the liue pipe rises, the thermostatic coil automatically rotates the 4secondary damper about the pivoting shaft 8, so as to reduce the a'dditional passage area until the temperature rises to the ,point where the perforations in the two dampers are entirely out of alinement, as shownin F ig. 1.

Since'this action of the spiral coil (or thermally responsive element) is independent of the setting. of the main damper, the user can start with any suitable position of the latter, and can also change position of the main damper at any time that this may be desirable, so that my arrangement combines the advantages of the usual manually adjustable damper with those of a mere thermostatically controlled damper.

Besides being inexpensive in construction and easily installed, my combination damper can be used equally well in flue pipes of heaters employing different fuels, and as an automatic substitute for the mere hand controlled dampers employed with so called economizers, hence I do not wish to be limited as to its use.

Moreover, while I have heretofore described my invention in an embodiment including numerous desirable details of construction and arrangement, I do not wish to be limited in these respects, as many changes might be made without departing either from the spirit of my invention or from the appended claims.

For example, instead of employing a thermostatic strip formed into a relatively flat coil, I may use an elongated spiral strip 25 surroundin a longer pivoting shaft 26 and shielded by a correspondingly longer housing 27, as shown in Fig. 4.

I claim as my invention:

1. The combination with aline pipe, of a rotatable shaft extending into the pipe radithe control member; the said means including a spiral coil; and a housin for the said coil. 2. The combination wit a substantially fiat damper for a flue pipe, the damper having perforations spaced from its center, of a control member adjacent to one face of the damper, pivoting means interposed between the damper and the control member for pivoting the control member coaxial with the damper, and thermally responsive means disposed radially inward of the said perforations and operatively interposed between the damper and the control member for moving the latter about the axis of the damper.

3. A damper for a flue pipe or the like coml prising a circular main plate, a pivoting shaft fast upon and coaxial with the main plate, a secondary member having two por? tions journaled on longitudinally spaced portions of the shaft; a thermally responsive member coiled about the shaft and connected at its ends respectively to the shaft and to the secondary member; the plate and the secondary member being provided with counterpart sectoral perforations adapted to be alined when the plates are in one relative rotational position, the said perforations being spaced radially outward from the thermally responsive member.

4:. For use in a iue pipe, the combination of a latdamper having perforations spaced from its center, a control member coaxial with and adjacent to the damper for controlling the passage of gas through the said perforations; a cup-shaped member having its mouth/end engaging the outer lface of the control member and secured to the latter, a`

shaft coaxial with the damper and the control member and extending through, the botl tom of the cup-shaped member to afford a" pivotal connection between the damper and the control member; and thermally responsive means housed by the cup-shaped member, the said means being operatively interposed between the damper and the control member for rotating t-he control member with respect to the damper in response to temperav ture changes.

Signed at Chicago, Illinois, February 13th, 1929.

ARTHUR C. MGWILLIAMS. 

